On-off indicator for radio apparatus



March 25, 1952 A. H. HAUN 2,590,314

ON-OFF INDICATOR FOR RADIO APPARATUS Filed May 12, 1945 :4 TTOQNEK Patented Mar. 25, 1952 ON -OFF INDICATOR FOR RADIO APPARATUS Arnold Haven Haun, Williamsport, Ind.,- assignor to Radio Corporation of America, a corporation of Delaware Application May 12, 1945, Serial No. 593,501

6 Claims.

The present invention relates in general to an oil-off indicator device for an energy consuming instrumentality and more particularly to a manual control knob for radio receivers and the like in which there is incorporated means for visibly indicating whether the receiver is on or off without consuming any energy from the source of supply for the operation of the instrumentality.

The invention is particularlyuseful in radio receivers that are powered by batteries. Since, in receivers of this type, battery drain is an important consideration, the usual dial light is wasteful of battery energy. Furthermore, such dial lights are not always dependable. If not replaced upon being burned out, there is no way of telling, with the volume down, whether the receiver is on or off. Frequently this may result in the complete discharge of the battery. The invention will also find utility in receivers energized from the power supply mains where it is desired to dispense with the usual dial lights.

It is therefore an object of the invention to provide a simple and reliable device for indicating the operative condition of a control member.

Another object of the invention is to provide a manual control knob for attachment to a control shaft, the operative and inoperative positions of which are visibly indicated by the control knob itself.

A further object of the invention is to provide .a control knob with means which is adapted to assume one position and in view of the operator when the control knob is rotated to one angular position and is adapted to assume another position out of view of the operator to thereby uncover a colored background when the control knob is rotated to a different angular position.

More specifically, it is an object of the invention to provide an on-off indicator for an electrical switch provided with a rotatable operating shaft which comprises a control knob afiixed to and rotatable with the shaft, the knob being formed with an elongated slot extending in a direction transverse to the shaft axis and with a viewing aperture axially disposed with respect to the knob and. shaft, and a circular disc contained within the slot, the slot being formed of such configuration that the disc is adapted, in the "off" position of the switch, to occupy a position in the slot in registry with the viewing aperture and, in the on position of the switch, to occupy a position in the slot which is out of registry with said aperture to thereby expose a distinctive background of the slot wall which is aligned with the viewing aperture.

"in connection with Fig. 2. A single viewing win- 56 The novel features characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and mode of operation together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings in which:

Fig. l is a view, in cross-section, of the control knob according to the invention;

Fig. 2 is a cross-sectional view of the knob taken along the line IIII of Fig. 1 and looking in the direction of the arrows. the knob being in the off position whereat the disc is in registry with the viewing aperture; and

Fig. 3 is a front or face view of the knob after having been rotated in a clockwise direction from the position shown in Fig. 2 through an angle sufficient to rotate the control shaft to operative position whereat the disc is caused to move away from and out of registry with the viewing aperture.

Referring first to Fig. l, the control knob, indicated in general by the reference character I, consists of a rotatable structure comprising a body portion 2 and a cap portion 3 of any suitable material, such as phenolic molding compound. The body 2 is formed with a hub 4 which is provided with a central bore 5 adapted to receive the end of a control shaft 6 of a rotatable operator (not shown), the knob being keyed to rotate with the shaft by any known suitable means. The body portion of the knob is also formed with a circular disc part i having a flat surface 8 which may be painted with any distinctive color for a purpose to appear hereinafter.

The knob cap 3 is provided with a peripheral portion 9 which is adapted to fit over the periphery of the disc part I and is joined thereto at It! by a thermoplastic cement. In order to provide a better gripping surface for the fingers of the operator the outer surface ll of portion 9 of the knob is knurled in the usual manner. The cap 3 is also provided with a circumferential shoulder portion I 2 which is in abutting relation with the peripheral edge portion of the surface 8 of disc part 1. A narrow substantially circular cut-out portion or passage-way I3 is formed within the cap 3 so that when the knob is assembled there is provided between the body and cap portions thereof a narrow channel or slot extending in a plane normal to the axis of shaft 6, the configuration of which will be explained dow or aperture I4 is formed at the center of can 3 and extends through to the slot or cut-out portion I3. If desired there may be fitted within the aperture a circular disc I4 of transparent substance such as glass or cellulose acetate.

As viewed in Fig. 2 the peripheral edge or shoulder portion I2 of channel I3 has formed integral therewith a substantially linear portion I5 which extends inwardly and then terminates in a semi-circular portion I6 which is slightly spaced from and is concentrically arranged with respect to the viewing aperture I4. Formed integrally with portion I5 is a second semi-circular portion I! which is joined with the shoulder portion I2 to form a substantially spiral track.

Disposed within the slot or narrow channel I3 is a circular gravity-controlled element or disc member I8 of metal or other suitable material. In the position shown in Fig. 2, which is assumed to be the angular position of the control knob at which the control shaft is in the inoperative position, the disc member I8 is retained within semi-circular portion I6 and is in complete registry with viewing aperture I4 (Fig. 1). Upon rotation of the control knob to the position shown in Fig. 3, which is assumed to cause rotation of the control shaft to its operative position, the disc member will fall away from the aperture into an obscured position thereby uncovering the flat surface 8 of the knob body which may be distinctively colored to provide a strongly contrasting appearance to that of the disc.

Depending upon the angular rotation of the knob thedisc will travel from its initial position within part I6 (Fig. 2), then along parts I5 and I2, and finally into part II. This construction is particularly useful in the case of a combined onoff and volume control switch commonly used in radio receivers so that sufficient travel for the metal disc may be provided to take care of wide changes in volume. Upon rotation of the control knob in the reverse direction to return the shaft to initial position or to turn 'the receiver off," the metal disc is caused to ride on the track surface formed by shoulder I2 and part I5 until it falls into its position shown in Fig. 2.

It will be seen therefore that I have provided a simple and reliable indicator device incorporated in a manual control knob, and one which may readily be constructed at low cost and which is particularly adapted for use in radio receivers.

While I have shown and described a preferred embodiment of my invention, it will be understood that various modifications and changes will occur to those skilled in the art without departing from the spirit and scope of this invention. I

therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim is:

1. An on-off indicator provided for operation with a rotatable operating shaft, comprising a control knob affixed to and rotatable with the shaft, said knob being formed with a slot extending in a direction transverse to the shaft axis and with a single viewing aperture axially disposed with respect to the knob at the center thereof and having a distinctive background, a semi-circular portion on said knob extending from the periphery into said slot and about said aperture and a circular disc contained within the slot, said slot being of such configuration that the disc is adapted in the off position of the switch to occupy a position in the semi-circular portion within the slot in registry with the viewing aperture and in the on position of the switch to gravitate to a position in the slot which is out of registry with said aperture and to thereby expose the distinctive background of the slot wall aligned with the viewing aperture.

2. An on-oif indicator provided for operation with a rotatable operating shaft, comprising a manual control knob aflixed to and rotatable with the shaft, said knob being formed with a narrow, substantially circular channel which extends in a plane normal to the shaft axis with a distinctive background and with a single viewing aperture at its center which communicates with said channel, means within the channel forming with a portion of the peripheral edge thereof a substantially spiral track about the major portion of said peripheral edge, and a circular disc within the channel positioned on said track, the arrangement being such that in the off position of the switch the disc occupies a position of rest on the track in registry with the viewing aperture and, during the rotation of the switch to its on" position, the disc gravitates on the track to a position out of registry with said aperture to thereby expose said distinctive background at the rear of the viewing aperture.

3. In an on-off indicator for an energy consuming instrumentality, said indicator having surfaces for indicating the rotatory position of a rotatable operator without consuming any energy from the source of supply for the operation of said instrumentality: rotatable structure for connection and rotation with the operator, said structure including a passageway; and a gravitycontrolled element movable with respect to said passageway under the influence of gravity from an obscured position within the passageway when the operator is in one rotatory position, to a visible position when the operator is in another rotatory position; said gravity-controlled element having a viewable surface strongly contrasting in appearance with respect to the other viewable portions of the indicator surface for providing an easily noticed change between the obscured and exposed conditions of the gravity-controlled element.

4. The combination as defined by claim 3 in which the viewable portions of the indicator surface and the viewable surface of the gravitycontrolled member are distinguished by a strongly contrasting color difference.

5. In an on-oif indicator for an energy consuming instrumentality, said indicator indicating whether a rotatable on-oif operator is in a rotatory position other than a predetermined limiting off" position, without consuming any energy from the source of supply for the operation of said instrumentality: rotatable structure for connection and rotation with the operator through an extended range of rotatory positions; said structure including a passageway having a background portion, and viewing means through which this background portion is viewable from the exterior; and a gravity-controlled member movable within the passageway under the influence of gravity; said passageway having bounding surfaces shaped to cause the gravity-controlled member to move into a background-blocking position when the operator is in one rotatory position, and to move into a background-unblocking position when the operator is in a closely adjacent rotatory position; one of said closely adjacent rotatory positions being the off position, and said background and gravity-controlled member having viewable surfaces strongly contrasting in appearance for providing an easily noticed change between blocked and unblocked background conditions.

6. In an on-off indicator for an energy consuming instrumentality, said indicator having surfaces for indicating the rotatory position of a rotatable operator without consuming any energy from the source of supply for the operation of said instrumentality, rotatable structure for connection and'rotation with the operator comprising an enclosed channel except for a viewing aperture formed at the center of the operator, a gravity-controlled disc contained within said channel and movable therein under the influence of gravity from an obscured position within the passageway when the operator is in one rotatory position to a visible position through the viewing aperture when the shaft is in another rotatory position, and a semi-circular portion extending from the periphery of the rotatable structure to partially enclose said disc in said channel in the viewable position.

ARNOLD HAVEN HAUN.

REFERENCES CITED The-following references are of record in the file of this patent:

UNITED STATES PATENTS 

